This invention relates to get deflecting devices particularly adaptable for controlling the flow direction of exhaust gases from a jet engine, and is particularly directed to a device for varying the gas exit area of the exhaust nozzle at the end of the rearmost pipe section of the jet deflecting device, wherein the jet deflecting is of the type having at least two rotatably interconnected pipe sections at the downstream end of a stationary engine jet pipe.
German Offenlegungsschrift No. 2,056,088 and U.S. Pat. No. 3,776,467 disclose jet deflecting devices of the type having at least two rotatably interconnected pipe sections at the downstream end of a stationary engine jet pipe for a jet engine. Such jet deflection devices are provided in order to deflect the exhaust gas jet of an aircraft jet engine from a horizontal direction to a direction having vertical components of efflux in order to selectively provide for horizontal or vertical flight of the aircraft.
Arrangements of this type include means providing jet deflection positions for short take-off, wherein the exhaust gas jet issues diagonally downwardly at an angle of 30.degree. to 45.degree. with respect to the longitudinal center line of the aircraft.
In the actuating mechanisms disclosed in the above references, the jet deflecting devices may be controlled for movement in horizontal, as well as vertical direction, whereby aircraft incorporating such mechanisms may rapidly achieve maneuvers such as changes in pitch or roll attitude which are achieved by rudder or elevator control in conventional aircraft.
In the arrangements of the above references, the rearmost rotatable pipe section of the jet deflecting devices are provided with variable nozzles, in order to control the gas exit area to suit the mass flow in after burning operations and to decrease the mass flow when the after burner is inoperative.
In the design of known jet deflecting devices of the type having rotatably interconnected pipe sections, little or no attention has been paid to the design of a nozzle actuating mechanism, whereby the variable nozzle may be actuated from a point on the stationary engine jet pipe while taking into account different jet deflection angles of at least the rearmost pipe section carrying the variable nozzles. Any suitable design of the nozzle actuating mechanism must necessarily consider the individual movements of the pipe sections through equal or different angles of rotation. In other words, the entire exhaust gas jet system should be variable angularly not only in a vertical plane, but also in a horizontal plane to achieve three-dimensional actuation, by focusing the nozzle on any point within the confines of the cone determined by the number of rotatably mounted pipe sections, and by the relative inclinations of the inlet and outlet areas of the pipe sections.